Math Is Fun Forum

Hi All

While calculating power from power spectral density , we generally integrate it over the entire range (infinity) of frequencies as the equation suggests. But in some calculations we take only the positive half of frequencies to calculate power even though the PSD occupies entire positive and negative range of frequencies (eg. two sided noise spectrum).

Can you please explain when when should we consider only + frequencies and when should we consider both + and - frequencies ?? Any special cases in such considerations ??

Thanks in advance
Praneeth